Vodafone working ok in the UK here running LTE rather than (dedicated) 4G or above.
Caller ID unknown has been quite troublesome over the years. As far as I understand your carrier has to transmit the ID data in a format suitable for your Dialer / Contacts app to translate to name / number.
Recently, I think one or two cases were fixed by fine tuning APN, associated with carrier upgrade of service perhaps to 4G / 5G.
In a 5G environment it seems IMS registration is important.
IMS Registration
The dial INFO check:
Wifi calling not working, e OS 3.5 on FP6 - #3 by tcecyk
Network preferences
Are also important to optimise on device:
Settings > Network and internet > Internet > your_carrier 
> Preferred network type
- Just to experiment you might try to downgrade the setting.
Perhaps identify your device and version [HOWTO] Give complete /e/OS version info easily for support, answers, comparison etc.